Improvement of storage quality of strawberries by pullulan coatings incorporated with cinnamon essential oil nanoemulsion

Effect of cinnamaldehyde-nanoemulsion and nanostructured lipid carriers on physicochemical attributes of reduced-nitrite sausages

This study aimed to produce cinnamaldehyde (CA)-loaded nanostructured lipid carriers (NLC) and nanoemulsion (NE) to replace nitrite in sausage. The NLC and NE droplet sizes were 132 and 116 nm with encapsulation efficiency of 98 and 96 %, respectively. In in vitro antimicrobial assessment, the free CA and NE showed higher microbial activity against S. aureus and E. coli than NLC. Meanwhile, NE showed a faster release profile for CA than NLC. Among the samples, NE and NE + nitrite indicated the lowest peroxide value (3.7 ± 0.1), TVBN amount (8.6 ± 0.2), acidity (0.3 ± 0.02), microbial quality (against E. coli, C. perfringens, lactic acid bacteria, psychrophilic bacteria, total mold and yeast, and total viable counts), and sensory attribute, while the NE + nitrite sample exhibited better color properties and higher oxymyoglobin content (5-10 % higher). Therefore, NE + nitrite can be the best choice due to supporting the different quality parameters of sausage.

Application of essential oils as slow-release antimicrobial agents in food preservation: Preparation strategies, release mechanisms and application cases

Food spoilage caused by foodborne microorganisms will not only cause significant economic losses, but also the toxins produced by some microorganisms will also pose a serious threat to human health. Essential oil (EOs) has significant antimicrobial activity, but its application in the field of food preservation is limited because of its volatile, insoluble in water and sensitive to light and heat. Therefore, in order to solve these problems effectively, this paper first analyzed the antibacterial effect of EOs as an antimicrobial agent on foodborne bacteria and its mechanism. Then, the application strategies of EOs as a sustained-release antimicrobial agent in food preservation were reviewed. On this basis, the release mechanism and application cases of EOs in different antibacterial composites were analyzed. The purpose of this paper is to provide technical support and solutions for the preparation of new antibacterial packaging materials based on plant active components to ensure food safety and reduce food waste.

Use of encapsulated pomegranate seed oil in novel coarse and nanosized materials for improving the storage life of strawberry

Different-sized pomegranate seed oil-based emulsions (coarse (CsP) and nanoemulsions (NsP): 1246 and 325 nm) were successfully prepared. Strawberries treated with NsP and CsP showed a significant decrease (p < 0.05) in yeast-mold counts (TMY) by 1.80 log CFU g-1, and mesophilic aerobic bacteria counts (TMAB) decreased (p < 0.05) by 0.91 log CFU g-1, respectively. CsP- and NsP-treated strawberries had a TPC of 74.45 and 82.35 mg GAE kg-1, respectively, while control samples had a TPC of 44.24 mg GAE kg-1. The strawberries treated with NsP exhibited the highest antioxidant capacity with 179.44 mol TEAC g-1. After treatment with a coarse emulsion, severity levels of A. niger and B. cinerea were 60 and 73 % while the nanoemulsion treatment significantly reduced severity levels to 55.3 and 56 %. The coarse and nanoemulsions may have potential use within the food industry owing to their antioxidant and antifungal properties as well as their ability to enhance strawberry quality and function.

Citric acid crosslinked carboxymethyl cellulose edible films: A case study on preserving freshness in bananas

The study involves the preparation and characterization of crosslinked-carboxymethyl cellulose (CMC) films using varying amounts of citric acid (CA) within the range 5 %-20 %, w/w, relative to the dry weight of CMC. Through techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, carbonyl content analysis, and gel fraction measurements, the successful crosslinking between CMC and CA is confirmed. The investigation includes an analysis of chemical structure, physical and optical characteristics, swelling behavior, water vapor transmission rate, moisture content, and surface morphologies. The water resistance of the cross-linked CMC films exhibited a significant improvement when compared to the non-crosslinked CMC film. The findings indicated that films crosslinked with 10 % CA demonstrated favorable properties for application as edible coatings. These transparent films, ideal for packaging, prove effective in preserving the quality and sensory attributes of fresh bananas, including color retention, minimized weight loss, slowed ripening through inhibiting amyloplast degradation, and enhanced firmness during storage.

Antimicrobial screening of pecan shell extract and efficacy of pecan shell extract-pullulan coating against Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus on blueberries

Pecan shell is considered an agricultural waste; however, it contains various bioactive compounds with potential inhibitory effect against microorganisms. This study evaluated the antimicrobial efficacy of pecan shell extract (PSE) in vitro using disc-diffusion method and in vivo on blueberries as an antimicrobial coating using pullulan. For in vitro study, 5 and 10 % of aqueous (A-PSE) or ethanol pecan shell extract (E-PSE) incorporated into pullulan film were tested against different bacterial and fungal strains. Pullulan film disc was used as control. The diameter of growth inhibition (mm) around discs was measured. For in vivo study, PSE-P (5 % w/v aqueous pecan shell extract+5 % w/v pullulan), P (5 % w/v pullulan) or control (water) were spray coated on blueberries inoculated (∼5 log CFU/g) with Listeria monocytogenes, Salmonella enterica or Staphylococcus aureus; and stored at 4 °C, 50 ± 10 % RH for 15 days. The effect of antimicrobial coating against pathogens and its impact on quality during storage were determined. A-PSE and E-PSE films were more effective against Gram-positive bacteria and showed no antifungal effect at tested concentrations when evaluated in vitro. Immediately after coating on blueberries, PSE-P significantly reduced Listeria monocytogenes by 2 log CFU/g and lowered survival until day 5 than control or P. Native aerobic microbial population was reduced (P < 0.05) by 0.7 log CFU/g immediately after coating. PSE-P coating or storage time had no significant effect (P > 0.05) on the survival of S. enterica, S. aureus and native fungal population. PSE-P maintained the firmness of blueberry with no significant effect on its color, TSS, and pH during 15 days storage. PSE-P significantly reduced (P < 0.05) the spoilage rate by 21 % than control (28.5 %) and P (37 %); and minimized (P < 0.05) weight loss during storage. Pecan shell extracts show promise as a potential antimicrobial compound whose application on various food products or packaging material could be further explored.

Antioxidant and antimicrobial effect of sodium alginate nanoemulsion coating enriched with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on food pathogenic bacteria

Today, microbial contamination in food is one of the major problems of the food industry and public health in general around the world. Foodborne illnesses, such as diarrheal diseases, kill many people around the world each year. The general objective of this study was to evaluate the antioxidant and antibacterial activity of sodium alginate nanoemulsion coating incorporated with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on Escherichia coli, and Listeria monocytogenes. To achieve this study, fresh chicken meat was used for this experiment. Listeria monocytogenes ATCC 19111 and Escherichia coli ATCC 35218 were obtained from the American Type Culture Collection (Manassas, VA, USA). After the preparation of the essential oil, the chemical composition of this essential oil was determined by using (GC-MS). The physicochemical properties of the nanoemulsion essential oil prepared were characterized and their antimicrobial activity was evaluated. The results showed that the GC-MS analysis of the volatile constituents of the Origanum vulgare essential oil compounds allowed the identification of 19 compounds representing 93.72% of the total oil. The major components detected in Origanum vulgare essential oil were pulegone (49.25%), eucalyptol (18.23%), and menthone (12.37%). About the Carum cupticum essential oil, 21 compounds representing 98.5% of the total oil were identified. The major components detected in Origanum vulgare essential oil were thymol (23.3%), p-cymene (17.5%), and γ-terpinene (16.8%). The best z-average (d.nm) is 483.4 nm (Carum cupticum essential oil + nano) followed by 470.1 nm (nanochitosan). The results of the antimicrobial test showed that the different preparations have a good inhibitory activity for the in vitro growth of Escherichia coli and Listeria monocytogenes. According to the MIC and MBC results of this study, the nanoemulsion also presented a good bacteriostatic activity against the two pathogenic bacteria tested in this study.

Bacillus subtilis Edible Films for Strawberry Preservation: Antifungal Efficacy and Quality at Varied Temperatures

Fungal infestations, particularly from Rhizopus stolonifer, pose significant post-harvest challenges for strawberries, compromising their shelf life and quality. Traditional preservation methods, including refrigeration, offer limited protection against such pathogens. This study introduces an innovative approach, utilizing edible films infused with Bacillus subtilis strains GOS 01 B-67748 and HFC 103, known for their antifungal properties. We demonstrate that these bioactive films not only inhibit fungal growth effectively but also enhance the preservation of strawberries at varying temperatures. The inclusion of Bacillus subtilis in edible films represents a significant advancement in extending the viability of strawberries, surpassing the efficacy of conventional methods. Our findings suggest a promising avenue for natural, safe food preservation techniques, aligning with current consumer preferences for additive-free products. This research contributes to the broader understanding of microbial-based food preservation strategies, offering potential applications across a range of perishable commodities.

Nanocellulose-based antimicrobial aerogels with humidity-triggered release of cinnamaldehyde

Active food packaging with controlled release behavior of volatile antimicrobials is highly desirable for enhancing the quality of fresh produce. In this study, humidity-responsive antimicrobial aerogels were developed using chitosan and dialdehyde nanocellulose, loading with cyclodextrin-cinnamaldehyde inclusion complexes (ICs) for achieving humidity-triggered release of the encapsulated antimicrobial agent. Results showed that the prepared aerogels had capable water absorption ability, which could be served as absorbent pads to take in excessive exudate from packaged fresh produce. More importantly, the accumulative release rate of cinnamaldehyde from the antimicrobial aerogels was significantly improved at RH 98 % compared to that at RH 70 %, which accordingly inactivated all the inoculated Escherichia coli, Staphylococcus aureus and Botrytis cinerea. Additionally, strawberries packaged with the antimicrobial aerogels remained in good conditions after 5 d of storage at 22 ± 1 °C. The prepared composite aerogels had the potential to extend the shelf life of fresh strawberries.

Exploring the potential of pullulan-based films and coatings for effective food preservation: A comprehensive analysis of properties, activation strategies and applications

Pullulan is naturally occurring polysaccharide exhibited potential applications for food preservation has gained increasing attention over the last half-century. Recent studies focused on efficient preservation and targeted inhibition using active composite ingredients and advanced technologies. This has led to the emergence of pullulan-based biofilm preservation. This review extensively studied the characteristics of pullulan-based films and coatings, including their mechanical strength, water vapor permeability, thermal stability, and potential as a microbial agent. Furthermore, the distinct characteristics of pullulan, production methods, and activation strategies, such as pullulan derivatization, various compounded ingredients (plant extracts, microorganisms, and animal additives), and other technologies (e.g., ultrasound), are thoroughly studied for the functional property enhancement of pullulan-based films and coatings, ensuring optimal preservation conditions for diverse food products. Additionally, we explore hypotheses that further illuminate pullulan's potential as an eco-friendly bioactive material for food packaging applications. In addition, this review evaluates various methods to improve the efficiency of the film-forming mechanism, such as improving the direct coating process, bioactive packaging films, and implementing layer-by-layer coatings. Finally, current analyses put forward suggestions for future advancement in pullulan-based bioactive films, with the aim of expanding their range of potential applications.

Bioactive properties of clove (Syzygium aromaticum) essential oil nanoemulsion: A comprehensive review

Syzygium aromaticum, commonly called clove, is a culinary spice with medical uses. Clove is utilized in cosmetics, medicine, gastronomy, and agriculture due to its abundance of bioactive components such as gallic acid, flavonoids, eugenol acetate, and eugenol. Clove essential oil has been revealed to have antibacterial, antinociceptive, antibacterial activities, antifungal, and anticancerous qualities. Anti-inflammatory chemicals, including eugenol and flavonoids, are found in clove that help decrease inflammation and alleviate pain. The anti-inflammatory and analgesic qualities of clove oil have made it a popular natural cure for toothaches and gum discomfort. Due to its therapeutic potential, it has been used as a bioactive ingredient in coating fresh fruits and vegetables. This review article outlines the potential food processing applications of clove essential oil. The chemical structures of components, bioactive properties, and medicinal potential of clove essential oil, including phytochemical importance in food, have also been thoroughly addressed.

Preparation of gelatin-chitosan bilayer film loaded citral nanoemulsion as pH and enzyme stimuli-responsive antibacterial material for food packaging

The responsive release of enzymes, pH, temperature, light and other stimuli is an effective means to reduce the loss of volatile active substances and control the release of active ingredients. The purpose of this study is to design a simple and rapid method to synthesize a multifunctional bilayer membrane, which has good mechanical properties, long-lasting pH and enzyme dual sensitive sustained release properties, and excellent antibacterial activity. The citral nanoemulsion was prepared by ultrasonic method, then the chitosan solution loaded with nanoemulsion was assembled on the gelatin film, and the uniform and smooth gelatin-chitosan bilayer film was successfully prepared. Compared with the control group, the bilayer film loaded with nanoemulsion showed better barrier performance, mechanical properties and antibacterial activity.

Nanoemulsion based edible coatings for quality retention of fruits and vegetables-decoding the basics and advancements in last decade

Fruits and vegetables (F&V) are highly perishable and have important contributions to nutritional and economic sustainability. Although the developing nations have shown an immense increase in the production of horticultural commodities, the post-harvest losses are significant and have an adverse impact on the resources, economy, and environment as well. Nanoemulsion-based carriers are recognized for their diversity, natural origin, and immense potential to restrict losses while boosting the functional attributes of produce. The recent findings attest to nanoemulsions potential for extending the shelf life, managing quality, and reducing the losses of the perishables for sustainable livelihood of the farmers. However, further studies are required to evaluate the biological fate, safety, or potential toxicity of the nanoemulsion-based edible coatings. This review precisely focuses on various matrices used in the production of nanoemulsions, fabrication methods, characterization techniques, and the use of natural emulsifiers instead of chemicals. The future research focus stresses on developing low-cost fabrication techniques for nanoemulsion, improvement of the transmission properties i. e gas transmission rate (GTR), water vapor transmission rate (WVTR), and enhancing the performance of monolayer, bilayer, and other composite nanoemulsion base films. This beyond reducing the postharvest losses shall also restrict burden of the food waste management and related environmental issues at the same time.

Photoantimicrobial chitosan-gelatin-pomegranate peel extract films for strawberries preservation: From microbiological analysis to in vivo safety assessment

This study aimed to investigate the application of biopolymeric materials (chitosan, gelatin, and pomegranate peel extract as photosensitizer) and antimicrobial photodynamic therapy (aPDT) on the physicochemical and microbial safety of strawberries. The photosensitizer potential of the materials was confirmed by a light-dose-dependent photobleaching profile. The application of light (525 nm; 50 J cm-2) decreased by >2 log CFU mL-1 the survival of Staphylococcus aureus on the surface of the photoactive-biopolymeric films. Moreover, the materials did not present in vivo cytotoxicity using Danio rerio (Zebrafish) as well as cytophytotoxic, genotoxic, or mutagenic potentials against Allium cepa plant model, which points out their safety to be used as films without posing a risk to the humans and the environment. The photoactive-polymeric coatings were able to maintain the strawberries weight, and the association with green light was 100 % effective in delaying fungal contamination. These coated-strawberries presented a significant reduction in S. aureus survival after light application (5.47-4.34 log CFU mL-1). The molecular level analysis of the photoactive compound cyanidin-3-glucoside indicates absorption on UV-Vis consistent with aPDT action. Therefore, this study showed that the antimicrobial effects of aPDT combined with photoactive-biopolymeric coatings were enhanced, while the quality of the strawberries was maintained.

Roles of polysaccharides-based nanomaterials in food preservation and extension of shelf-life of food products: A review

In food production sectors, food spoilage and contamination are major issues that threaten and negatively influence food standards and safety. Several physical, chemical, and biological methods are used to extend the shelf-life of food products, but they have their limitations. Henceforth, researchers and scientists resort to novel methods to resolve these existing issues. Nanomaterials-based extension of food shelf life has broad scope rendering a broad spectrum of activity including high antioxidant and antimicrobial activity. Numerous research investigations have been made to identify the possible roles of nanoparticles in food preservation. A wide range of nanomaterials via different approaches is ultimately applied for food preservation. Among them, chemically synthesized methods have several limitations, unlike biological synthesis. However, biological synthesis protocols are quite expensive and laborious. Predominant studies demonstrated that nanoparticles can protect fruits and vegetables by preventing microbial contamination. Though several nanomaterials designated for food preservation are available, detailed knowledge of the mechanism remains unclear. Hence, this review aims to highlight the various nanomaterials and their roles in increasing the shelf life of food products. Adding to the novel market trends, nano-packaging will open new frontiers and prospects for ensuring food safety and quality.

Advances in Designing Essential Oil Nanoformulations: An Integrative Approach to Mathematical Modeling with Potential Application in Food Preservation

Preservation of foods, along with health and safety issues, is a growing concern in the current generation. Essential oils have emerged as a natural means for the long-term protection of foods along with the maintenance of their qualities. Direct applications of essential oils have posed various constraints to the food system and also have limitations in application; hence, encapsulation of essential oils into biopolymers has been recognized as a cutting-edge technology to overcome these challenges. This article presents and evaluates the strategies for the development of encapsulated essential oils on the basis of fascination with the modeling and shuffling of various biopolymers, surfactants, and co-surfactants, along with the utilization of different fabrication processes. Artificial intelligence and machine learning have enabled the preparation of different nanoemulsion formulations, synthesis strategies, stability, and release kinetics of essential oils or their bioactive components from nanoemulsions with improved efficacy in food systems. Different mathematical models for the stability and delivery kinetics of essential oils in food systems have also been discussed. The article also explains the advanced application of modeling-based encapsulation strategies on the preservation of a variety of food commodities with their intended implication in food and agricultural industries.

Edible Coatings as a Natural Packaging System to Improve Fruit and Vegetable Shelf Life and Quality

In the past years, consumers have increased their interest in buying healthier food products, rejecting those products with more additives and giving preference to the fresh ones. Moreover, the current environmental situation has made society more aware of the importance of reducing the production of plastic and food waste. In this way and considering the food industry's need to reduce food spoilage along the food chain, edible coatings have been considered eco-friendly food packaging that can replace traditional plastic packaging, providing an improvement in the product's shelf life. Edible coatings are thin layers applied straight onto the food material's surface that are made of biopolymers that usually incorporate other elements, such as nanoparticles or essential oils, to improve their physicochemical properties. These materials must provide a barrier that can prevent the passage of water vapor and other gasses, microbial growth, moisture loss, and oxidation so shelf life can be extended. The aim of this review was to compile the current data available to give a global vision of the formulation process and the different ways to improve the characteristics of the coats applied to both fruits and vegetables. In this way, the suitability of compounds in by-products produced in the food industry chain were also considered for edible coating production.

Pullulan-Based Active Coating Incorporating Potassium Metabisulfite Maintains Postharvest Quality and Induces Disease Resistance to Soft Rot in Kiwifruit

Soft rot is a severe postharvest disease of kiwifruit that causes enormous economic losses annually. In this study, we aimed to explore an effective pullulan-based active coating, incorporating food additives to reduce soft rot and extend the shelf life of cold-stored kiwifruit. The results showed that 1 g/L potassium metabisulfite could completely inhibit the mycelial growth of Diaporthe sp., Botryosphaeria dothidea, Phomopsis sp. and Alternaria sp., which were the primary pathogens of kiwifruit soft rot. Furthermore, the pullulan coating, combined with a 10 g/L potassium metabisulfite group, had a decay rate 46% lower than the control (CK) group and maintained fruit quality at the end of shelf life. The retention of physicochemical properties such as soluble solid content (SSC), firmness, weight loss and respiration rate also confirmed the efficacy of the treatment. In addition, at the end of shelf life, pullulan coating, combined with potassium metabisulfite, increased the accumulation of total phenolic content (37.59%) and flavonoid content (9.28%), maintained a high energy charge (51.36%), and enhanced superoxide dismutase (SOD) (6.27%), peroxidase (POD) (62.50%), catalase (CAT) (84.62%) and phenylalanine ammonia lyase (PAL) (24.61%) enzyme activities as well as initiating the upregulation of their gene expression levels. As a result, the disease resistance of fruit was improved, and the occurrence of soft rot was delayed. Overall, this study demonstrated that using the pullulan-based active coating incorporating potassium metabisulfite treatment effectively controlled soft rot and retarded the senescence of postharvest kiwifruit.

Encapsulation and delivery systems of cinnamon essential oil for food preservation applications

Food safety threats and deterioration due to the invasion of microorganisms has led to economic losses and food-borne diseases in the food industry; so, development of natural food preservatives is urgently needed when considering the safety of chemically synthesized preservatives. Because of its outstanding antioxidant and antibacterial properties, cinnamon essential oil (CEO) is considered a promising natural preservative. However, CEO's low solubility and easy degradability limits its application in food products. Therefore, some encapsulation and delivery systems have been developed to improve CEO efficiency in food preservation applications. This work discusses the chemical and techno-functional properties of CEO, including its key components and antioxidant/antibacterial properties, and summarizes recent developments on encapsulation and delivery systems for CEO in food preservation applications. Since CEO is currently added to most biopolymeric films/coatings (BFCs) for food preservation, most studies have shown that encapsulation systems can improve the food preservation performance of BFCs containing CEOs. It has been confirmed that various delivery systems could improve the stability and controlled-release properties of CEO, thereby enhancing its ability to extend the shelf life of foods. These encapsulation techniques include spray drying, emulsion systems, complex coacervation (nanoprecipitation), ionic gelation, liposomes, inclusion complexation (cyclodextrins, silica), and electrospinning.

Fabrication, characterization and antimicrobial activity of chitosan/tragacanth gum/polyvinyl alcohol composite films incorporated with cinnamon essential oil nanoemulsion

The aim of this investigation was to prepare and characterize active composite films made of chitosan (CS), tragacanth gum (TG), polyvinyl alcohol (PVA) and loaded with different concentrations of cinnamon essential oil (CEO) nanoemulsion (CEO, 2 and 4 % v/v). For this purpose, the amount of CS was fixed and the ratio of TG to PVA (90:10, 80:20, 70:30, and 60:40) was considered variable. The physical (thickness and opacity), mechanical, antibacterial and water-resistance properties of the composite films were evaluated. According to the microbial tests, the optimal sample was determined and evaluated with several analytical instruments. CEO loading increased the thickness and EAB of composite films, while decreasing light transmission, tensile strength, and water vapor permeability. All the films containing CEO nanoemulsion had antimicrobial properties, but this activity was higher against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) than Gram-negative types (Escherichia coli (O157:H7) and Salmonella typhimurium). According to the results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD), the interaction between the components of the composite film was confirmed. It can be concluded that the CEO nanoemulsion can be incorporated in CS/TG/PVA composite films and successfully used as active and environmentally friendly packaging.

Fabrication, characterization, and interventions of protein, polysaccharide and lipid-based nanoemulsions in food and nutraceutical delivery applications: A review

The fabrication and application of nanoemulsions for incorporating and delivering diverse bioactive compounds, particularly hydrophobic substances, is becoming an increasing focus of research with the potential to improve the nutritional and health status of individuals. Constant advancements in nanotechnological approaches aid in the creation of nanoemulsions using diverse biopolymers such as proteins, peptides, polysaccharides, and lipids to improve the stability, bioactivity, and bioavailability of active hydrophilic and lipophilic compounds. This article provides a comprehensive overview of various techniques used to create and characterize nanoemulsions as well as theories for understanding their stability. The article also highlights the advancement of nanoemulsions in boosting the bioaccessibility of nutraceuticals to help advance their potential use in various food and pharmaceutical formulations.

Formulation of nanoemulsion carriers containing Pennyroyal (Mentha pulegium) and Gijavash (Froriepia subpinnata) essential oils for enriching Doogh (Iranian dairy drink)

Today, the increasing use of chemical preservatives in foods is considered one of the main problems in food industries. This study aimed to produce the pasteurised Doogh (Iranian yogurt drink) containing a nanoemulsion of essential oil (EO) with appropriate quality. A factorial test based on a completely randomised design with two treatments in three levels, including EO type (pennyroyal, Gijavash, and their equal combination) and a control sample was applied to assess the physicochemical and sensory properties of Doogh. The highest negative zeta potential and antioxidant activity percentage were observed in the sample containing the nanoemulsion of pennyroyal and enriched with a combination of two essential oils. The microbial evaluation results indicated that the total microorganism count was minimised in the Doogh containing the nanoemulsion of Gijavash. The nanoemulsions of pennyroyal and Gijavash can be added into Doogh formulation to produce a new product with maximum sensory acceptability.

Chitosan based encapsulation of Valeriana officinalis essential oil as edible coating for inhibition of fungi and aflatoxin B1 contamination, nutritional quality improvement, and shelf life extension of Citrus sinensis fruits

In this study, a novel chitosan nanoemulsion coating embedded with Valeriana officinalis essential oil (Ne-VOEO) was synthesized in order to improve the postharvest quality of Citrus sinensis fruits against infesting fungi, and aflatoxin B₁ (AFB₁) mediated nutritional deterioration. The developed nanoemulsion was characterized through SEM, FTIR, XRD, and DLS analyses. The nanoemulsion showed controlled delivery of VOEO responsible for effective inhibition of Aspergillus flavus, A. niger, A. versicolor, Penicillium italicum, and Fusarium oxysporum growth at 6.5, 5.0, 4.0, 5.5, and 3.5 μL/mL, respectively and AFB₁ production at 5.0 μL/mL. The biochemical and molecular mechanism of aflatoxigenic A. flavus inhibition, and AFB₁ diminution was associated with impairment in ergosterol biosynthesis, methylglyoxal production, and stereo-spatial binding of valerianol in the cavity of Ver-1 protein. During in vivo investigation, Ne-VOEO coating potentially restrained the weight loss, and respiratory rate of C. sinensis fruits with delayed degradation of soluble solids, titrable acidity, pH, and phenolic contents along with maintenance of SOD, CAT, APX activities (p < 0.05) and sensory attributes under specific storage conditions. Based on overall findings, Ne-VOEO nanoemulsion could be recommended as green, and smart antifungal coating agent in prolonging the shelf-life of stored fruits with enhanced AFB₁ mitigation.

Edible coating enriched with cinnamon oil reduces the oxidative stress and improves the quality of strawberry fruit stored at room temperature

BACKGROUND

The present study aimed to assess the impact of a starch/gelatine coating containing cinnamon oil on selected quality attributes and redox status in strawberry fruit stored at room temperature (72 h).

RESULTS

Research showed that the application of cinnamon oil to an edible coating allows an improvement of the quality of strawberry fruit stored at room temperature. The cinnamon oil coating inhibits the development of yeast and mould, and reduces loss of soluble solids and ascorbic acid during 72 h storage at room temperature. Moreover, the coating with cinnamon oil clearly reduced the level of oxidative stress, which was manifested by a lower level of reactive oxygen species, as well as a lower activity of antioxidant enzymes. The elimination of oxidative stress in the cinnamon oil-coated fruit also contributed to lower PARP1 mRNA expression, inhibiting the metabolism of NAD⁺ and reducing ATP losses.

CONCLUSION

The coating of strawberry fruit with a starch/gelatine biofilm containing cinnamon oil is an effective method for delaying postharvest senescence of fruit and the storage degradation of tissue. © 2023 Society of Chemical Industry.

Caraway Nanoemulsion Gel: A Potential Antibacterial Treatment against Escherichia coli and Staphylococcus aureus

Novel antibiotics are needed due to the rise of antibiotic-resistant pathogens. Traditional antibiotics are ineffective due to antibiotic-resistant microorganisms, and finding alternative therapies is expensive. Hence, plant-derived caraway (Carum carvi) essential oils and antibacterial compounds have been selected as alternatives. In this, caraway essential oil as an antibacterial treatment was investigated using a nanoemulsion gel. Using the emulsification technique, a nanoemulsion gel was developed and characterized in terms of particle size, polydispersity index, pH, and viscosity. The results showed that the nanoemulsion had a mean particle size of 137 nm and an encapsulation efficiency of 92%. Afterward, the nanoemulsion gel was incorporated into the carbopol gel and was found to be transparent and uniform. The gel had in vitro cell viability and antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The gel safely delivered a transdermal drug with a cell survival rate of over 90%. With a minimal inhibitor concentration (MIC) of 0.78 mg/mL and 0.78 mg/mL, respectively, the gel demonstrated substantial inhibition for E. coli and S. aureus. Lastly, the study demonstrated that caraway essential oil nanoemulsion gels can be efficient in treating E. coli and S. aureus, laying the groundwork for the use of caraway essential oil as an alternative to synthetic antibiotics in the treatment of bacterial infections.

Electrospun polyvinyl alcohol/chitosan nanofibers incorporated with 1,8-cineole/cyclodextrin inclusion complexes: Characterization, release kinetics and application in strawberry preservation

Development of food packaging systems containing essential oils (EOs) has gained increased attention recently. However, the instability of EOs restricts their application. Therefore, effective encapsulation of EOs is demanded for their protection and controlled release. In this work, 1,8-cineole, the major component in Eucalyptus globulus essential oil, was encapsulated into hydroxypropyl-β-cyclodextrin to form an inclusion complex, which was then incorporated into polyvinyl alcohol and chitosan composite polymer to fabricate nanofibrous film via electrospinning. The film with 40% (w/w) of inclusion complexes showed enhanced barrier and mechanical properties, and the release of 1,8-cineole from the film was sustained and dominated by the non-Fick diffusion. Moreover, this film could extend the shelf life of strawberries to 6 days at 25 ℃. This work suggested dual encapsulation of EOs by cyclodextrin and electrospun nanofibers is an ideal strategy to improve the availability of EOs, and the produced film is promising for food preservation.

Development and characterization of chitosan/bacterial cellulose/pullulan bilayer film with sustained release curcumin

A natural biopolymer bilayer film based on chitosan and bacterial cellulose with a protective layer of pullulan was developed by a two-step solution casting method. Curcumin was incorporated as an active antioxidant and antibacterial agent into the inner layer. The films with different curcumin concentrations were systematically characterized. Fourier transform infrared spectroscopy and X-ray diffraction analyses showed high compatibility between curcumin and the polysaccharide matrix through intermolecular interactions, which was verified by enhanced mechanical and barrier properties. The curcumin incorporation improved the thermal stability by >35.4 %, along with lower visible and ultraviolet light transmittance (< 8.6 %) and water solubility (< 25.1 %). The film had both antibacterial and antioxidant properties, and the sustained release of curcumin was largest (> 58.8 %) in the fatty food simulant lasting for over 155 h. The results suggested that the film containing 0.2 % curcumin had ideal physical and functional properties, suggesting its potential as a novel packaging material for the preservation of high-fat food.

An all-cellulose sponge with a nanofiller-assisted hierarchical cellular structure for fruit maintaining freshness

Cellulose sponges with compressibility and resilience are an ideal packaging material for fruits with fragile skin. Here, a soft and elastic all-cellulose sponge (CS) with a hierarchical cellular structure was fabricated, where the long molecular chain cellulose constructed major pores, the cellulose at nanoscale acted as an elastic nanofiller to fill the gaps of long molecular chain cellulose fibers and constructed minor pores. With these two kinds of pores, this structure can absorb strain hierarchically. The sponge can protect fruits from mechanical damage when dropped or repeated vibration. Furthermore, the CS modified with chlorogenic acid (C-CGAS) had excellent antibacterial and antifungal abilities. Therefore, C-CGAS could extend the storage time of strawberries to 18 days without any microbial invasion, which is the longest storage time reported thus far. This study provides a new idea for the preparation of polymer sponges and a new design for the development of antimicrobial packaging materials.

Nanoencapsulation application to prolong postharvest shelf life

This review offers our opinion on current and future trends regarding nanoencapsulation interventions to extend postharvest shelf life of stored grains, fruits, and vegetables. Herein, we considered two major factors influencing postharvest shelf life for comments: aerobic food spoilage microorganisms and stored pests. Nanoemulsions, edible/active coatings, and nanopackaging loading essential oils as antimicrobial, antioxidant, or pesticide showed promising results in prolonged shelf life at room/cold storage without compromising quality, organoleptic properties, and postharvest physiology. Trends with nanoencapsulation using plant-based pesticides as agrochemical-free methods to keep produce fresh longer were commented as potential candidates for prolonging the shelf life of stored grains and fruits at the postharvest stage. Research with potential large-scale feasibility is intensive, but safety assessment is required and remains little explored.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.

Bio-nanocomposite edible coatings based on arrowroot starch/cellulose nanocrystals/carnauba wax nanoemulsion containing essential oils to preserve quality and improve shelf life of strawberry

This study investigated the effects of bio-nanocomposite coatings developed using arrowroot starch (AA), cellulose nanocrystals (CNC), carnauba wax nanoemulsion (CWN), and Cymbopogon martinii and Mentha spicata essential oils (CEO and MEO, respectively) on the physicochemical, microbiological, bioactive, antioxidant, and aromatic characteristics of strawberries cv. 'Oso Grande' in refrigerated storage for 12 days. The coatings improved the shelf life and stability of strawberries, minimizing their weight loss (2.6-3.9 %), as well as changes in color and texture (except for those coated with CEO), titratable acidity, pH, soluble solids, anthocyanins, phenolic compounds, ascorbic acid content, and antioxidant activity compared with uncoated control strawberries. The bio-nanocomposite coatings containing MEO and CEO also exhibited antimicrobial activity, reduced visible fungal deterioration (40-60 %), and reduced microbial load (3.59-4.03 log CFU g^-1 for mesophilic aerobic bacteria and 4.45-5.22 log CFU g^-1 for fungi and yeast) during storage. They also significantly reduced the severity of decay caused by inoculation with Botrytis cinerea or Rhizopus stolonifer. The coatings altered the volatile profile of the fruits during storage, decreasing aldehyde and alcohol concentrations and increasing ester concentrations. Thus, these bio-nanocomposite coatings, especially those containing MEO, can be used as antimicrobial coating materials to preserve the post-harvest quality of fresh strawberries.

Characterization and Application in Packaging Grease of Gelatin-Sodium Alginate Edible Films Cross-Linked by Pullulan

Gelatin–sodium alginate-based edible films cross-linked with pullulan were prepared using the solution casting method. FTIR spectroscopy demonstrated the existence of hydrogen bonding interactions between the components, and scanning electron microscopy observed the component of the films, revealing electrostatic interactions and thus explaining the differences in the properties of the blend films. The best mechanical properties and oxygen barrier occurred at a 1:1 percentage of pullulan to gelatin (GP11) with sodium alginate dosing for modification. Furthermore, GP11 demonstrated the best thermodynamic properties by DSC analysis, the highest UV barrier (94.13%) and the best oxidation resistance in DPPH tests. The results of storage experiments using modified edible films encapsulated in fresh fish liver oil showed that GP11 retarded grease oxidation by inhibiting the rise in peroxide and anisidine values, while inappropriate amounts of pullulan had a pro-oxidative effect on grease. The correlation between oil oxidation and material properties was investigated, and water solubility and apparent color characteristics were also assessed.

Sodium alginate/gum arabic/glycerol multicomponent edible films loaded with natamycin: Study on physicochemical, antibacterial, and sweet potatoes preservation properties

Sweet potato (Ipomonea batatas Lam) is easily damaged due to its thin skin, which is limited in shelf life and causes enormous economic losses in the food industry. A new type of safe, non-toxic, and edible antibacterial functional film was developed with sodium alginate (2.5 %), gum arabic (1 %), glycerol (2 %), and natamycin as an antimicrobial agent in this study. The physical and antibacterial properties of films, such as thickness, chromaticity, water vapor permeability, tensile strength, and elongation at break, were studied. Furthermore, the antibacterial film was applied in the preservation of sweet potatoes. The results showed that natamycin emulsion had good compatibility with sodium alginate. Besides reducing the transparency of the composite membrane, the mechanical properties, barrier properties, and thermal stability of the composite film were significantly enhanced by the addition of natamycin prepared by a pH-cycle method. When the concentration of natamycin in the membrane solution reached 40 μg/mL or more, the antibacterial film had a noticeable inhibitory effect on the growth of molds, and yeasts, significantly enhancing the bacteriostatic effect of the base film. During the sweet potatoes storage, the water content, total starch content, Vc content, and flavonoid glycoside content of sweet potato showed a downward trend. However, the treatment of antibacterial film containing natamycin could slow down the physiological and quality changes of sweet potatoes during conventional storage, and the sweet potatoes still had good processing quality after 120 days of storage.

Bio-based antibacterial food packaging films and coatings containing cinnamaldehyde: A review

As a typical bioactive compound from the bark and leaves of the trees of the genus Cinnamomum, cinnamaldehyde (CIN) is natural and safe. Its excellent antibacterial activity against various foodborne microorganisms is growingly regarded as a promising additive for improving and enhancing the properties of bio-based packaging films/coatings. This review systematically summarized the bio-based food packaging films/coatings containing CIN developed recently. The effects of CIN incorporation on physical and chemical properties of the antibacterial food packaging films/coatings, including thickness, color index, transparency, water content, water solubility, water contact angle, mechanical performances, water barrier performances, and antibacterial performances, were discussed. Simultaneously, this work also concluded that an explanation of the antibacterial mechanism of CIN and preparation methods of bio-based packaging films/coatings containing CIN/CIN carriers. Notably, the incorporation of CIN into the films/coatings could enhance their antibacterial performance extend the shelf-life of various foods, such as fish, meats, vegetables, fruits, and other perishable food, while improving their physical and chemical properties. Although incorporating CIN into food packaging films/coatings has been extensively studied, long-term follow-up research on the human safety of active food packaging films/coatings containing CIN needs to be carried out.

Nanoemulsions containing some plant essential oils as promising formulations against Culex pipiens (L.) larvae and their biochemical studies

The chemical composition of cypress, lavender, lemon eucalyptus, and tea tree oils has been investigated using gas chromatography/mass spectrometry (GC/MS). These oils were tested for larvicidal activity against Culex pipiens alongside their nanoemulsions (NEs) and conventional emulsifiable concentrates (ECs). Oil-in-water (O/W) NEs preparation was based on a high-energy ultra-sonication technique. The effect of independent variables of preparation on the different outputs was studied using the response surface method to obtain the optimum preparation technique. The droplet sizes of prepared NEs were significantly different (71.67, 104.55, 211.07, and 70.67 for cypress, lavender, lemon eucalyptus, and Tea tree NEs, respectively). The zeta potentials of NEs were recorded to have a high negatively charge (-28.4, -22.2, -23.6, and - 22.3 mV for cypress, lavender, lemon eucalyptus, and tea tree NEs, respectively). The results showed that the tea tree oil has the most significant effect with LC₅₀ = 60.02 and 57.10 mg/L after 24 and 48 h of exposure, respectively. In comparison, cypress oil proved the lowest toxicity with LC₅₀ values of 202.24 and 180.70 mg/L after 24 and 48 h, respectively. However, lavender oil does not show any effect against larvae at tested concentrations. In addition, pure oil exhibited the lowest larvicidal activity. However, the EC of all tested insecticides slightly improved the toxic action against the larvae. While the NEs showed significantly high toxicity compared to the EO and EC. An in vivo assessment of acetylcholine esterase (AChE), adenosine triphosphatase (ATPase), and gamma-aminobutyric acid transaminase (GABA-T) revealed that the NEs exhibited higher activity than the pure oils and ECs. This work describes these oils with potential use against C. pipiens larvae as eco-friendly products.

Soft and elastic silver nanoparticle-cellulose sponge as fresh-keeping packaging to protect strawberries from physical damage and microbial invasion

Strawberry is a nutritious food that is susceptible to mechanical injury and microbiological infection. Traditional coatings for strawberry packaging provide resistance against microbial infection but not against mechanical damage. In this study, a soft and elastic cellulose sponge modified with silver nanoparticles (AgNPs@CS-1:1) was prepared as strawberry packaging material, and it provided effective protection against mechanical damage. In addition, after 1000 cyclic compression, AgNPs@CS-1:1 presented only 16.80% unrecoverable deformation and still had elasticity, suggesting its fatigue resistance and durable protection for strawberry against damage caused by repeated vibrations during transportation. In addition, AgNPs@CS-1:1 had good antibacterial (E. coli and S. aureus) and antifungal (Rhizopus stolonifer) abilities. The storage time of strawberries packaged by AgNPs@CS-1:1 was extended to 12 days without microbial invasion. Thus, AgNPs@CS-1:1 provided dual protection at the physical and microbial levels. This study proposes a new method for the preservation of strawberries based on the utilization of cellulose.

Recent developments in industrial applications of nanoemulsions

Nanotechnology is being utilized in various industries to increase the quality, safety, shelf-life, and functional performance of commercial products. Nanoemulsions are thermodynamically unstable colloidal dispersions that consist of at least two immiscible liquids (typically oil and water), as well as various stabilizers (including emulsifiers, texture modifiers, ripening inhibitors, and weighting agents). They have unique properties that make them particularly suitable for some applications, including their small droplet size, high surface area, good physical stability, rapid digestibility, and high bioavailability. This article reviews recent developments in the formulation, fabrication, functional performance, and gastrointestinal fate of nanoemulsions suitable for use in the pharmaceutical, cosmetic, nutraceutical, and food industries, as well as providing an overview of regulatory and health concerns. Nanoemulsion-based delivery systems can enhance the water-dispersibility, stability, and bioavailability of hydrophobic bioactive compounds. Nevertheless, they must be carefully formulated to obtain the required functional attributes. In particular, the concentration, size, charge, and physical properties of the nano-droplets must be taken into consideration for each specific application. Before launching a nanoscale product onto the market, determination of physicochemical characteristics of nanoparticles and their potential health and environmental risks should be evaluated. In addition, legal, consumer, and economic factors must also be considered when creating these systems.

Polysaccharide-Based Edible Films Incorporated with Essential Oil Nanoemulsions: Physico-Chemical, Mechanical Properties and Its Application in Food Preservation—A Review

Edible films with essential oils (EOs) are becoming increasingly popular as an alternative to synthetic packaging due to their environmentally friendly properties and ability as carriers of active compounds. However, the required amounts of EOs to impart effective antimicrobial properties generally exceed the organoleptic acceptance levels. However, by nanoemulsifying EOs, it is possible to increase their antimicrobial activity while reducing the amount required. This review provides an overview of the physico-chemical and mechanical properties of polysaccharide-based edible films incorporated with EOs nanoemulsions and of their application to the preservation of different food types. By incorporating EOs nanoemulsions into the packaging matrix, these edible films can help to extend the shelf-life of food products while also improving the quality and safety of the food product during storage. It can be concluded that these edible films have the potential to be used in the food industry as a green, sustainable, and biodegradable method for perishable foods preservation.

Potential of engineered nanostructured biopolymer based coatings for perishable fruits with Coronavirus safety perspectives

Fresh fruits are prioritized needs in order to fulfill the required health benefits for human beings. However, some essential fruits are highly perishable with very short shelf-life during storage because of microbial growth and infections. Thus improvement of fruits shelf-life is a serious concern for their proper utlization without generation of huge amount of fruit-waste. Among various methods employed in extension of fruits shelf-life, design and fabrication of edible nanocoatings with antimicrobial activities have attracted considerable interest because of their enormous potential, novel functions, eco-friendly nature and good durability. In recent years, scientific communities have payed increased attention in the development of advanced antimicrobial edible coatings to prolong the postharvest shelf-life of fruits using hydrocolloids. In this review, we attempted to highlight the technical breakthrough and recent advancements in development of edible fruit coating by the application of various types of agro-industrial residues and different active nanomaterials incorporated into the coatings and their effects on shelf-life of perishable fruits. Improvements in highly desired functions such as antioxidant/antimicrobial activities and mechanical properties of edible coating to significantly control the gases (O₂/CO₂) permeation by the incorporation of nanoscale natural materials as well as metal nanoparticles are reviewed and discussed. In addition, by compiling recent knowledge, advantages of coatings on fruits for nutritional security during COVID-19 pandemic are also summarized along with the scientific challenges and insights for future developments in fabrication of engineered nanocoatings.

Antimicrobial effect of laurel essential oil nanoemulsion on food-borne pathogens and fish spoilage bacteria

This research aimed to apply nanotechnology for nanoformulation of Laurus nobilis essential oil (EO) by ultrasonic emulsification method and characterization of nano-form: particle size, viscosity, polydispersity index, thermodynamic stability, and surface tension. The antimicrobial activity of laurel EO nanoemulsion (LEON) and laurel EO was also investigated against a panel of ten food-borne pathogens and fish spoilage bacteria. The GC-MS analysis of EO revealed that 1,8-Cineole was the main volatile compound. According to disc-diffusion results, LEON was more effective against Gram-positive pathogen bacteria of Staphylococcus aureus and Enterococcus faecalis than EO. Laurel oil demonstrated a higher inhibitory effect against fish spoilage bacteria (6.19 to 18.5 mm). The MICs values of LEON and laurel EO ranged from 6.25 to >25 mg/mL and from 1.56 to >25 mg/mL, respectively. Nanoemulsion and oil exhibited the best bactericidal activity against Pseudomonas luteola. Therefore, LEON can be developed as a natural antimicrobial agent in food industry.